For one, Ostrovsky suggested, commandos could have approached the ship from under water and disabled the propellers, letting the activists drift for days until their food supplies ran out. He added that Israeli soldiers should not have fast-roped into a crowd as they had, instead suggesting that it would have been more productive to board the ship from the front and back, then work inward.

Israel faced heavy criticism in an emergency session of the United Nations Security Council on Monday in response to its deadly attack on an aid flotilla trying to breach the Gaza blockade, but attempts to issue a formal statement stalled after the United States rejected the strong condemnation sought by Turkey.

UN Secretary General Ban Ki-moon said Monday he was "shocked" by a deadly Israeli raid on a Gaza-bound aid flotilla and demanded a full investigation.

"I am shocked by reports of killings and injuries of people on boats carrying supplies for Gaza," the UN chief said at a press conference following the opening in Uganda of a key conference on the International Criminal Court.

As Prime Minister Benjamin Netanyahu heads to Washington in a much-feted effort to restore damaged ties with the United States, new tensions in East Jerusalem threaten to rekindle a diplomatic row over Jewish building beyond the Green Line in the city.

On Saturday lawyers served eviction notices to two Palestinian families in the Sheikh Jarrah neighborhood, a focus of clashes between Arab residents and settlers.

But Sasha Polakow-Suransky, the American academic who uncovered the documents while researching a book on the military and political relationship between the two countries, said the denials were disingenuous, because the minutes of meetings Peres held with the then South African defence minister, PW Botha, show that the apartheid government believed an explicit offer to provide nuclear warheads had been made.